Our study explains why it is important to implement the aspects of sustainability in order to successfully converge and break out of the trap of medium development, and presents the main findings of the MNB Sustainability Report and Index based on a self-developed quantification-purpose methodology. The socio-economic system of a country is considered sustainable if its environmental, social, financial and real economy resources are used in a sustainable way to achieve and maintain longterm prosperity. The MNB’s Sustainability Index ranks Hungary 15th among the 27 EU member states in 2021, which is slightly better than the average ranking of the Visegrád countries, but slightly behind the EU average. There is room for improvement in all four priority areas, with the identification of the greatest scope for convergence in the financial and social sustainability dimensions. In line with the frameworks of international organisations (UN, OECD) with a strong track record in sustainability, the MNB report helps to identify key areas of potential sustainability strengths and reserves, thus supporting, on the one hand, long-term, strategic policy-making, specialised research in the field of sustainability and, on the other hand, sustainable convergence.